|
The infant hearing disorders are the most common birth defects, among the five first of disability in our country. The second national sample survey of persons with disabilities, our children with hearing disability patients account for about 10% of the total number of hearing disabled, and the number is still a rate of 2 million to 4 million people a year increments. After the birth of a baby from 6 months to 1 year old, is the most critical period of language development, hearing impairment in infancy than the occult, if not timely detection and intervention will seriously affect children with speech, cognitive and emotional development. Many factors that cause hearing damage, drug-induced deafness is considered to be one of the main causes of hearing loss. However, drug ototoxicity forecasting system and detection technology can not meet the needs of the research and development of new drugs and drug safety evaluation. This paper studies the ototoxic the three aminoglycoside antibiotic gentamicin (Gentamycin), neomycin (Neomycin) and streptomycin (streptomycin) damage to the hair cells of zebrafish larvae, and hearing-related gene expression to establish a simple, sensitive, rapid, visually detect drug ototoxicity zebrafish models and methods. On this basis, the application of three cephalosporins - cefotaxime (Cefotaxime Sodium), cefazolin (Cefazolin Sodium) and cefprozil (cis-Cefprozil) and a cephalosporin impurities - trans cefprozil (trans- cefprozil) the model further verification, in order to explore the effectiveness of the model. The main results of this study are as follows: (1) through the study of three known to have a clear ototoxicity of aminoglycoside antibiotics, the establishment of the zebrafish drug-induced ototoxicity model, the model testing standards: (1 ) development of zebrafish ear capsule structure abnormal; (2) ear sac that surrounds the five parts (MI1, MI2, 01,02, I04) neuromast hair cells appear to reduce the number of, or the ear capsule or lateral line neuromast hair The cells were missing a whole; (3) 48 hpf embryos and hearing development related gene expression levels upward or downward adjustments; (4) 5 DPF zebra fish juveniles shaft bent back in the stationary state. The first two indicators is necessary to detect the end point. (2) the use of the model, the four may be related to aminoglycoside antibiotics with a different mechanism of ototoxicity cephalosporins ototoxicity were evaluated. Teratogenic and lethal strength of four cephalosporin compounds as follows: the cefazolin GT; trans cefprozil gt; the cis cefprozil gt; cefotaxime. The toxic effects of these four cephalosporin compounds on zebrafish have shown the body axis, abnormal heart and yolk sac development, specifically major developmental lag, trunk flexion, pigmentary abnormalities, pericardial sac enlargement the ventral proximal main vein congestion; and the four compounds on zebrafish ear capsule structure can cause irreversible changes, including the utricle morphological variation (spherical) or disappear, smaller balloon, and the spacing between the two larger and abnormal semicircular canal structure; were caused the ear capsule around and the number of hair cells of the lateral line even colliculus reduced or missing, the phenomenon has a concentration-dependent manner, showing a significant difference. (3) at the genetic level, these four compounds are caused by the plurality of hearing-related gene expression is lowered, wherein the gene, there is also a type of gene described hearing impairment is a result of the joint action of multiple genes. Intrinsically linked to these genetic changes pending further study. In the established model, aminoglycosides and cephalosporins zebrafish colliculus and hair cell death injury; target genes involved, which not only proved that reported in the literature for these two types of antibiotics in animal experiments in ototoxic mechanism of action different conclusions, further validates the effectiveness of our model.
|